386/admin/properties-regexp-function.html


<!DOCTYPE html>

<html>
  <head>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
  <meta name="viewport" content="width=device-width,initial-scale=1">
  <meta http-equiv="x-ua-compatible" content="ie=edge">
  <meta name="lang:clipboard.copy" content="Copy to clipboard">
  <meta name="lang:clipboard.copied" content="Copied to clipboard">
  <meta name="lang:search.language" content="en">
  <meta name="lang:search.pipeline.stopwords" content="True">
  <meta name="lang:search.pipeline.trimmer" content="True">
  <meta name="lang:search.result.none" content="No matching documents">
  <meta name="lang:search.result.one" content="1 matching document">
  <meta name="lang:search.result.other" content="# matching documents">
  <meta name="lang:search.tokenizer" content="[\s\-]+">

  
    <link href="https://fonts.gstatic.com/" rel="preconnect" crossorigin>
    <link href="https://fonts.googleapis.com/css?family=Roboto+Mono:400,500,700|Roboto:300,400,400i,700&display=fallback" rel="stylesheet">

    <link href="https://fonts.googleapis.com/css2?family=Alata&family=Open+Sans:ital,wght%400,300;0,400;0,600;1,400&display=swap" rel="stylesheet">
    <style>
      body,
      input {
        font-family: "Roboto", "Helvetica Neue", Helvetica, Arial, sans-serif
      }

      code,
      kbd,
      pre {
        font-family: "Roboto Mono", "Courier New", Courier, monospace
      }
    </style>
  

  <link rel="stylesheet" href="../_static/stylesheets/application.css"/>
  <link rel="stylesheet" href="../_static/stylesheets/application-palette.css"/>
  <link rel="stylesheet" href="../_static/stylesheets/application-fixes.css"/>
  
  <link rel="stylesheet" href="../_static/fonts/material-icons.css"/>
  
  <meta name="theme-color" content="2196f3">
  <script src="../_static/javascripts/modernizr.js"></script>
  
  
    <title>Regular expression function properties &#8212; Trino 386 Documentation</title>
    <link rel="stylesheet" href="../_static/pygments.css" type="text/css" />
    <link rel="stylesheet" href="../_static/material.css" type="text/css" />
    <link rel="stylesheet" type="text/css" href="../_static/copybutton.css" />
    <link rel="stylesheet" type="text/css" href="../_static/trino.css" />
    <script id="documentation_options" data-url_root="../" src="../_static/documentation_options.js"></script>
    <script src="../_static/jquery.js"></script>
    <script src="../_static/underscore.js"></script>
    <script src="../_static/doctools.js"></script>
    <script src="../_static/language_data.js"></script>
    <script src="../_static/clipboard.min.js"></script>
    <script src="../_static/copybutton.js"></script>
    <script async="async" src="https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.7/latest.js?config=TeX-AMS-MML_HTMLorMML"></script>
    <script type="text/x-mathjax-config">MathJax.Hub.Config({"tex2jax": {"inlineMath": [["\\(", "\\)"]], "displayMath": [["\\[", "\\]"]], "processRefs": false, "processEnvironments": false}})</script>
    <link rel="index" title="Index" href="../genindex.html" />
    <link rel="search" title="Search" href="../search.html" />
    <link rel="next" title="Spill to disk" href="spill.html" />
    <link rel="prev" title="Web UI properties" href="properties-web-interface.html" />
  
   
    <script async src="https://www.googletagmanager.com/gtag/js?id=UA-133457846-1"></script>
    <script>
      window.dataLayer = window.dataLayer || [];
      function gtag(){dataLayer.push(arguments);}
      gtag('js', new Date());
      gtag('config', 'UA-133457846-1');
      gtag('config', 'AW-1036784065');
      window._linkedin_data_partner_ids = ['2842796'];
    </script>
    <script async src="https://snap.licdn.com/li.lms-analytics/insight.min.js"></script>
  </head>
  <body dir=ltr
        data-md-color-primary= data-md-color-accent=>
  
  <svg class="md-svg">
    <defs data-children-count="0">
      
      <svg xmlns="http://www.w3.org/2000/svg" width="416" height="448" viewBox="0 0 416 448" id="__github"><path fill="currentColor" d="M160 304q0 10-3.125 20.5t-10.75 19T128 352t-18.125-8.5-10.75-19T96 304t3.125-20.5 10.75-19T128 256t18.125 8.5 10.75 19T160 304zm160 0q0 10-3.125 20.5t-10.75 19T288 352t-18.125-8.5-10.75-19T256 304t3.125-20.5 10.75-19T288 256t18.125 8.5 10.75 19T320 304zm40 0q0-30-17.25-51T296 232q-10.25 0-48.75 5.25Q229.5 240 208 240t-39.25-2.75Q130.75 232 120 232q-29.5 0-46.75 21T56 304q0 22 8 38.375t20.25 25.75 30.5 15 35 7.375 37.25 1.75h42q20.5 0 37.25-1.75t35-7.375 30.5-15 20.25-25.75T360 304zm56-44q0 51.75-15.25 82.75-9.5 19.25-26.375 33.25t-35.25 21.5-42.5 11.875-42.875 5.5T212 416q-19.5 0-35.5-.75t-36.875-3.125-38.125-7.5-34.25-12.875T37 371.5t-21.5-28.75Q0 312 0 260q0-59.25 34-99-6.75-20.5-6.75-42.5 0-29 12.75-54.5 27 0 47.5 9.875t47.25 30.875Q171.5 96 212 96q37 0 70 8 26.25-20.5 46.75-30.25T376 64q12.75 25.5 12.75 54.5 0 21.75-6.75 42 34 40 34 99.5z"/></svg>
      
    </defs>
  </svg>
  
  <input class="md-toggle" data-md-toggle="drawer" type="checkbox" id="__drawer">
  <input class="md-toggle" data-md-toggle="search" type="checkbox" id="__search">
  <label class="md-overlay" data-md-component="overlay" for="__drawer"></label>
  <a href="#admin/properties-regexp-function" tabindex="1" class="md-skip"> Skip to content </a>
  <div id="announcement">
  <div id="announcement-content">
    Presto SQL is now Trino
    <a href="https://trino.io/blog/2020/12/27/announcing-trino.html" target="_blank">Read why &raquo;</a>
  </div>
</div>
<header class="md-header" data-md-component="header">
  <nav class="md-header-nav md-grid">
    <div class="md-flex navheader">
      <div class="md-flex__cell md-flex__cell--shrink">
        <a href="/" title="Trino"
           class="md-header-nav__button md-logo">
          
              <img src="../_static/trino.svg" height="26"
                   alt="Trino 386 Documentation logo">
          
        </a>
      </div>
      <div class="md-flex__cell md-flex__cell--shrink">
        <label class="md-icon md-icon--menu md-header-nav__button" for="__drawer"></label>
      </div>
      <div class="md-flex__cell md-flex__cell--stretch">
        <div class="md-flex__ellipsis md-header-nav__title" data-md-component="title">
          <span class="md-header-nav__topic">Trino 386 Documentation</span>
          <span class="md-header-nav__topic"> Regular expression function properties </span>
        </div>
      </div>
      <div class="md-flex__cell md-flex__cell--shrink">
        <label class="md-icon md-icon--search md-header-nav__button" for="__search"></label>
        
<div class="md-search" data-md-component="search" role="dialog">
  <label class="md-search__overlay" for="__search"></label>
  <div class="md-search__inner" role="search">
    <form class="md-search__form" action="../search.html" method="GET" name="search">
      <input type="text" class="md-search__input" name="q" placeholder="Search"
             autocapitalize="off" autocomplete="off" spellcheck="false"
             data-md-component="query" data-md-state="active">
      <label class="md-icon md-search__icon" for="__search"></label>
      <button type="reset" class="md-icon md-search__icon" data-md-component="reset" tabindex="-1">
        &#xE5CD;
      </button>
    </form>
    <div class="md-search__output">
      <div class="md-search__scrollwrap" data-md-scrollfix>
        <div class="md-search-result" data-md-component="result">
          <div class="md-search-result__meta">
            Type to start searching
          </div>
          <ol class="md-search-result__list"></ol>
        </div>
      </div>
    </div>
  </div>
</div>

      </div>
      
        <div class="md-flex__cell md-flex__cell--shrink">
          <div class="md-header-nav__source">
            <a href="https://github.com/trinodb/trino" title="Go to repository" class="md-source" data-md-source="github">

    <div class="md-source__icon">
      <svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" viewBox="0 0 24 24" width="28" height="28">
        <use xlink:href="#__github" width="24" height="24"></use>
      </svg>
    </div>
  
  <div class="md-source__repository">
    Trino
  </div>
</a>
          </div>
        </div>
      
      
  <script src="../_static/javascripts/version_dropdown.js"></script>
  <script>
    var json_loc = "../../versions.json",
        target_loc = "../../",
        text = "Versions";
    $( document ).ready( add_version_dropdown(json_loc, target_loc, text));
  </script>
  

    </div>
  </nav>
</header>

  
  <div class="md-container">
    
    
    <!-- empty -->
    <main class="md-main">
      <div class="md-main__inner md-grid" data-md-component="container">
        
          <div class="md-sidebar md-sidebar--primary" data-md-component="navigation">
            <div class="md-sidebar__scrollwrap">
              <div class="md-sidebar__inner">
                <nav class="md-nav md-nav--primary" data-md-level="0">
  <label class="md-nav__title md-nav__title--site" for="__drawer">
    <a href="/" title="Trino" class="md-nav__button md-logo">
      
        <img src="../_static/trino.svg" alt=" logo" width="48" height="48">
      
    </a>
    <a href="../index.html"
       title="Trino 386 Documentation">Trino 386 Documentation</a>
  </label>
    <div class="md-nav__source">
      <a href="https://github.com/trinodb/trino" title="Go to repository" class="md-source" data-md-source="github">

    <div class="md-source__icon">
      <svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" viewBox="0 0 24 24" width="28" height="28">
        <use xlink:href="#__github" width="24" height="24"></use>
      </svg>
    </div>
  
  <div class="md-source__repository">
    Trino
  </div>
</a>
    </div>
  
  
  <ul class="md-nav__list">
    <li class="md-nav__item">
    
    
      <a href="../overview.html" class="md-nav__link">Overview</a>
      
    
    </li>
    <li class="md-nav__item">
    
    
      <a href="../installation.html" class="md-nav__link">Installation</a>
      
    
    </li>
    <li class="md-nav__item">
    
    
      <a href="../client.html" class="md-nav__link">Clients</a>
      
    
    </li>
    <li class="md-nav__item">
    
    
      <a href="../security.html" class="md-nav__link">Security</a>
      
    
    </li>
    <li class="md-nav__item">
    
    
      <a href="../admin.html" class="md-nav__link">Administration</a>
      <ul class="md-nav__list"> 
    <li class="md-nav__item">
    
    
      <a href="web-interface.html" class="md-nav__link">Web UI</a>
      
    
    </li>
    <li class="md-nav__item">
    
    
      <a href="tuning.html" class="md-nav__link">Tuning Trino</a>
      
    
    </li>
    <li class="md-nav__item">
    
    
      <a href="jmx.html" class="md-nav__link">Monitoring with JMX</a>
      
    
    </li>
    <li class="md-nav__item">
    
    
      <a href="properties.html" class="md-nav__link">Properties reference</a>
      <ul class="md-nav__list"> 
    <li class="md-nav__item">
    
    
      <a href="properties-general.html" class="md-nav__link">General</a>
      
    
    </li>
    <li class="md-nav__item">
    
    
      <a href="properties-resource-management.html" class="md-nav__link">Resource management</a>
      
    
    </li>
    <li class="md-nav__item">
    
    
      <a href="properties-query-management.html" class="md-nav__link">Query management</a>
      
    
    </li>
    <li class="md-nav__item">
    
    
      <a href="properties-spilling.html" class="md-nav__link">Spilling</a>
      
    
    </li>
    <li class="md-nav__item">
    
    
      <a href="properties-exchange.html" class="md-nav__link">Exchange</a>
      
    
    </li>
    <li class="md-nav__item">
    
    
      <a href="properties-task.html" class="md-nav__link">Task</a>
      
    
    </li>
    <li class="md-nav__item">
    
    
      <a href="properties-write-partitioning.html" class="md-nav__link">Write partitioning</a>
      
    
    </li>
    <li class="md-nav__item">
    
    
      <a href="properties-writer-scaling.html" class="md-nav__link">Writer scaling</a>
      
    
    </li>
    <li class="md-nav__item">
    
    
      <a href="properties-node-scheduler.html" class="md-nav__link">Node scheduler</a>
      
    
    </li>
    <li class="md-nav__item">
    
    
      <a href="properties-optimizer.html" class="md-nav__link">Optimizer</a>
      
    
    </li>
    <li class="md-nav__item">
    
    
      <a href="properties-logging.html" class="md-nav__link">Logging</a>
      
    
    </li>
    <li class="md-nav__item">
    
    
      <a href="properties-web-interface.html" class="md-nav__link">Web UI</a>
      
    
    </li>
    <li class="md-nav__item">
    
    
    <input class="md-toggle md-nav__toggle" data-md-toggle="toc" type="checkbox" id="__toc">
    <label class="md-nav__link md-nav__link--active" for="__toc"> Regular expression function </label>
    
      <a href="#" class="md-nav__link md-nav__link--active">Regular expression function</a>
      
        
<nav class="md-nav md-nav--secondary">
    <label class="md-nav__title" for="__toc">Contents</label>
    <ul class="md-nav__list" data-md-scrollfix="">
        <li class="md-nav__item"><a href="#regex-library" class="md-nav__link"><code class="docutils literal notranslate"><span class="pre">regex-library</span></code></a>
        </li>
        <li class="md-nav__item"><a href="#re2j-dfa-states-limit" class="md-nav__link"><code class="docutils literal notranslate"><span class="pre">re2j.dfa-states-limit</span></code></a>
        </li>
        <li class="md-nav__item"><a href="#re2j-dfa-retries" class="md-nav__link"><code class="docutils literal notranslate"><span class="pre">re2j.dfa-retries</span></code></a>
        </li>
    </ul>
</nav>
      
    
    </li></ul>
    
    </li>
    <li class="md-nav__item">
    
    
      <a href="spill.html" class="md-nav__link">Spill to disk</a>
      
    
    </li>
    <li class="md-nav__item">
    
    
      <a href="resource-groups.html" class="md-nav__link">Resource groups</a>
      
    
    </li>
    <li class="md-nav__item">
    
    
      <a href="session-property-managers.html" class="md-nav__link">Session property managers</a>
      
    
    </li>
    <li class="md-nav__item">
    
    
      <a href="dist-sort.html" class="md-nav__link">Distributed sort</a>
      
    
    </li>
    <li class="md-nav__item">
    
    
      <a href="dynamic-filtering.html" class="md-nav__link">Dynamic filtering</a>
      
    
    </li>
    <li class="md-nav__item">
    
    
      <a href="graceful-shutdown.html" class="md-nav__link">Graceful shutdown</a>
      
    
    </li>
    <li class="md-nav__item">
    
    
      <a href="fault-tolerant-execution.html" class="md-nav__link">Fault-tolerant execution</a>
      
    
    </li></ul>
    
    </li>
    <li class="md-nav__item">
    
    
      <a href="../admin.html#event-listeners" class="md-nav__link">Event listeners</a>
      
    
    </li>
    <li class="md-nav__item">
    
    
      <a href="../optimizer.html" class="md-nav__link">Query optimizer</a>
      
    
    </li>
    <li class="md-nav__item">
    
    
      <a href="../connector.html" class="md-nav__link">Connectors</a>
      
    
    </li>
    <li class="md-nav__item">
    
    
      <a href="../functions.html" class="md-nav__link">Functions and operators</a>
      
    
    </li>
    <li class="md-nav__item">
    
    
      <a href="../language.html" class="md-nav__link">SQL language</a>
      
    
    </li>
    <li class="md-nav__item">
    
    
      <a href="../sql.html" class="md-nav__link">SQL statement syntax</a>
      
    
    </li>
    <li class="md-nav__item">
    
    
      <a href="../develop.html" class="md-nav__link">Developer guide</a>
      
    
    </li>
    <li class="md-nav__item">
    
    
      <a href="../appendix.html" class="md-nav__link">Appendix</a>
      
    
    </li>
    <li class="md-nav__item">
    
    
      <a href="../release.html" class="md-nav__link">Release notes</a>
      
    
    </li>
  </ul>
  

</nav>
              </div>
            </div>
          </div>
          <div class="md-sidebar md-sidebar--secondary" data-md-component="toc">
            <div class="md-sidebar__scrollwrap">
              <div class="md-sidebar__inner">
                
<nav class="md-nav md-nav--secondary">
    <label class="md-nav__title" for="__toc">Contents</label>
    <ul class="md-nav__list" data-md-scrollfix="">
        <li class="md-nav__item"><a href="#regex-library" class="md-nav__link"><code class="docutils literal notranslate"><span class="pre">regex-library</span></code></a>
        </li>
        <li class="md-nav__item"><a href="#re2j-dfa-states-limit" class="md-nav__link"><code class="docutils literal notranslate"><span class="pre">re2j.dfa-states-limit</span></code></a>
        </li>
        <li class="md-nav__item"><a href="#re2j-dfa-retries" class="md-nav__link"><code class="docutils literal notranslate"><span class="pre">re2j.dfa-retries</span></code></a>
        </li>
    </ul>
</nav>
              </div>
            </div>
          </div>
        
        <div class="md-content">
          <article class="md-content__inner md-typeset" role="main">
            
  
<h1 id="admin-properties-regexp-function--page-root">Regular expression function properties<a class="headerlink" href="#admin-properties-regexp-function--page-root" title="Permalink to this headline">#</a></h1>
<p>These properties allow tuning the <a class="reference internal" href="../functions/regexp.html"><span class="doc">Regular expression functions</span></a>.</p>

<h2 id="regex-library"><code class="docutils literal notranslate"><span class="pre">regex-library</span></code><a class="headerlink" href="#regex-library" title="Permalink to this headline">#</a></h2>
<ul class="simple">
<li><p><strong>Type:</strong> <a class="reference internal" href="properties.html#prop-type-string"><span class="std std-ref">string</span></a></p></li>
<li><p><strong>Allowed values:</strong> <code class="docutils literal notranslate"><span class="pre">JONI</span></code>, <code class="docutils literal notranslate"><span class="pre">RE2J</span></code></p></li>
<li><p><strong>Default value:</strong> <code class="docutils literal notranslate"><span class="pre">JONI</span></code></p></li>
</ul>
<p>Which library to use for regular expression functions.
<code class="docutils literal notranslate"><span class="pre">JONI</span></code> is generally faster for common usage, but can require exponential
time for certain expression patterns. <code class="docutils literal notranslate"><span class="pre">RE2J</span></code> uses a different algorithm,
which guarantees linear time, but is often slower.</p>


<h2 id="re2j-dfa-states-limit"><code class="docutils literal notranslate"><span class="pre">re2j.dfa-states-limit</span></code><a class="headerlink" href="#re2j-dfa-states-limit" title="Permalink to this headline">#</a></h2>
<ul class="simple">
<li><p><strong>Type:</strong> <a class="reference internal" href="properties.html#prop-type-integer"><span class="std std-ref">integer</span></a></p></li>
<li><p><strong>Minimum value:</strong> <code class="docutils literal notranslate"><span class="pre">2</span></code></p></li>
<li><p><strong>Default value:</strong> <code class="docutils literal notranslate"><span class="pre">2147483647</span></code></p></li>
</ul>
<p>The maximum number of states to use when RE2J builds the fast,
but potentially memory intensive, deterministic finite automaton (DFA)
for regular expression matching. If the limit is reached, RE2J falls
back to the algorithm that uses the slower, but less memory intensive
non-deterministic finite automaton (NFA). Decreasing this value decreases the
maximum memory footprint of a regular expression search at the cost of speed.</p>


<h2 id="re2j-dfa-retries"><code class="docutils literal notranslate"><span class="pre">re2j.dfa-retries</span></code><a class="headerlink" href="#re2j-dfa-retries" title="Permalink to this headline">#</a></h2>
<ul class="simple">
<li><p><strong>Type:</strong> <a class="reference internal" href="properties.html#prop-type-integer"><span class="std std-ref">integer</span></a></p></li>
<li><p><strong>Minimum value:</strong> <code class="docutils literal notranslate"><span class="pre">0</span></code></p></li>
<li><p><strong>Default value:</strong> <code class="docutils literal notranslate"><span class="pre">5</span></code></p></li>
</ul>
<p>The number of times that RE2J retries the DFA algorithm, when
it reaches a states limit before using the slower, but less memory
intensive NFA algorithm, for all future inputs for that search. If hitting the
limit for a given input row is likely to be an outlier, you want to be able
to process subsequent rows using the faster DFA algorithm. If you are likely
to hit the limit on matches for subsequent rows as well, you want to use the
correct algorithm from the beginning so as not to waste time and resources.
The more rows you are processing, the larger this value should be.</p>


          </article>
        </div>
      </div>
    </main>
  </div>
  <footer class="md-footer">
    <div class="md-footer-nav">
      <nav class="md-footer-nav__inner md-grid">
          
            <a href="properties-web-interface.html" title="Web UI properties"
               class="md-flex md-footer-nav__link md-footer-nav__link--prev"
               rel="prev">
              <div class="md-flex__cell md-flex__cell--shrink">
                <i class="md-icon md-icon--arrow-back md-footer-nav__button"></i>
              </div>
              <div class="md-flex__cell md-flex__cell--stretch md-footer-nav__title">
                <span class="md-flex__ellipsis">
                  <span
                      class="md-footer-nav__direction"> Previous </span> Web UI properties </span>
              </div>
            </a>
          
          
            <a href="spill.html" title="Spill to disk"
               class="md-flex md-footer-nav__link md-footer-nav__link--next"
               rel="next">
            <div class="md-flex__cell md-flex__cell--stretch md-footer-nav__title"><span
                class="md-flex__ellipsis"> <span
                class="md-footer-nav__direction"> Next </span> Spill to disk </span>
            </div>
            <div class="md-flex__cell md-flex__cell--shrink"><i
                class="md-icon md-icon--arrow-forward md-footer-nav__button"></i>
            </div>
          
        </a>
        
      </nav>
    </div>
    <div class="md-footer-meta md-typeset">
      <div class="md-footer-meta__inner md-grid">
        <div class="md-footer-copyright">
        </div>
      </div>
    </div>
  </footer>
  <script src="../_static/javascripts/application.js"></script>
  <script>app.initialize({version: "1.0.4", url: {base: ".."}})</script>
  </body>
</html>